In a statement on December 5, Abadi said the entry of "around one armed battalion with a number of tanks and cannons" into the northern Nineveh Province was a violation of Iraq's sovereignty.

Iraq's Foreign Ministry described the entry of an estimated 150 Turkish soldiers and 25 tanks as "an incursion" and rejected any military operation that was not coordinated with the federal government in Baghdad.

Iraqi President Fuad Massum also described the Turkish deployment as "a violation of international norms and law."

Turkish sources said the Turkish troops were deployed to provide training for Iraqi troops near Mosul, a city of more than 1 million people that Islamic State (IS) fighters captured in July 2014.

The Turkish sources said Turkey already had troops in Iraq's autonomous Kurdistan region, and the United States and other countries involved in fighting IS there were aware it was moving some troops to the Mosul area.

U.S. officials in Washington said they were aware of Turkey's move, but it was not coordinated with the anti-IS coalition operating in northern Iraq.